摘要：
http://www.williammalone.com/articles/create-html5-canvas-javascript-drawing-app/http://www.w3.org/TR/2dcontext/http://google-web-toolkit.googlecode.com/svn/javadoc/2.2/com/google/gwt/canvas/dom/client/Context2d.html 阅读全文
摘要：
interface CanvasRenderingContext2D { // back-reference to the canvas readonly attribute HTMLCanvasElement canvas; // state void save(); // push state on state stack void restore(); // pop state stack and restore state // transformations (default transform is the identity matrix) void scale(in... 阅读全文